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Revision e6da7c9fed111ba1243297ee6eda8e24ae11c384 authored by Eric Sandeen on 23 May 2009, 19:30:12 UTC, committed by Felix Blyakher on 02 June 2009, 03:59:38 UTC 
xfs: fix overflow in xfs_growfs_data_private
 
In the case where growing a filesystem would leave the last AG
too small, the fixup code has an overflow in the calculation
of the new size with one fewer ag, because "nagcount" is a 32
bit number.  If the new filesystem has > 2^32 blocks in it
this causes a problem resulting in an EINVAL return from growfs:

 # xfs_io -f -c "truncate 19998630180864" fsfile
 # mkfs.xfs -f -bsize=4096 -dagsize=76288719b,size=3905982455b fsfile
 # mount -o loop fsfile /mnt
 # xfs_growfs /mnt

meta-data=/dev/loop0             isize=256    agcount=52,
agsize=76288719 blks
         =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=3905982455, imaxpct=5
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=32768, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=0
realtime =none                   extsz=4096   blocks=0, rtextents=0
xfs_growfs: XFS_IOC_FSGROWFSDATA xfsctl failed: Invalid argument

Reported-by: richard.ems@cape-horn-eng.com
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
1 parent 1f23920
Raw File
string_helpers.c 
/*
 * Helpers for formatting and printing strings
 *
 * Copyright 31 August 2008 James Bottomley
 */
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/string_helpers.h>

/**
 * string_get_size - get the size in the specified units
 * @size:	The size to be converted
 * @units:	units to use (powers of 1000 or 1024)
 * @buf:	buffer to format to
 * @len:	length of buffer
 *
 * This function returns a string formatted to 3 significant figures
 * giving the size in the required units.  Returns 0 on success or
 * error on failure.  @buf is always zero terminated.
 *
 */
int string_get_size(u64 size, const enum string_size_units units,
		    char *buf, int len)
{
	const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
				   "EB", "ZB", "YB", NULL};
	const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
				 "EiB", "ZiB", "YiB", NULL };
	const char **units_str[] = {
		[STRING_UNITS_10] =  units_10,
		[STRING_UNITS_2] = units_2,
	};
	const unsigned int divisor[] = {
		[STRING_UNITS_10] = 1000,
		[STRING_UNITS_2] = 1024,
	};
	int i, j;
	u64 remainder = 0, sf_cap;
	char tmp[8];

	tmp[0] = '\0';
	i = 0;
	if (size >= divisor[units]) {
		while (size >= divisor[units] && units_str[units][i]) {
			remainder = do_div(size, divisor[units]);
			i++;
		}

		sf_cap = size;
		for (j = 0; sf_cap*10 < 1000; j++)
			sf_cap *= 10;

		if (j) {
			remainder *= 1000;
			do_div(remainder, divisor[units]);
			snprintf(tmp, sizeof(tmp), ".%03lld",
				 (unsigned long long)remainder);
			tmp[j+1] = '\0';
		}
	}

	snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
		 tmp, units_str[units][i]);

	return 0;
}
EXPORT_SYMBOL(string_get_size);
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